Challenge 3: Rewrite with /x — Possible Solution
====================================================================

Original:
    /^(\w+)@(\w+\.\w+)$/

Rewritten with /x:

my $email_pattern = qr/
    ^
    ( \w+ )        # the username part, before the @
    @
    ( \w+ \. \w+ ) # the domain part: word characters, a literal dot, more word characters
    $
/x;

use strict;
use warnings;
use feature 'say';

my $email = "ada\@example.com";
if ($email =~ $email_pattern) {
    say "Username: $1, Domain: $2";
}

Output:
Username: ada, Domain: example.com

WHY THIS WORKS AS AN ANSWER
------------------------------
The rewritten pattern reuses every piece of the original regex
completely unchanged in MEANING — ^, (\w+), @, (\w+\.\w+), and $ all
still mean exactly what they meant before — only the FORMATTING
changed, per the chapter's own description of what /x actually does:
it "ignores whitespace... and allows # comments," not a different
matching behavior.

Each significant regex token is placed on its own line, reusing the
chapter's own multi-line /x layout from its job-reference-pattern
example, with a # comment (also reused directly from that same
example) explaining what each piece is responsible for — the username
part, the literal @, and the domain part.

The \. inside ( \w+ \. \w+ ) keeps its backslash escape exactly as in
the original — the chapter's own warn-box-adjacent point that only
whitespace is ignored under /x, not the actual regex metacharacters
themselves, so \. still means "a literal dot" and not "any character,"
exactly as it did in the original single-line version.

Testing both against the same email confirms the rewrite is behavior-
preserving: $1 and $2 populate with "ada" and "example.com" exactly
as the original, unformatted pattern would have produced.